NY Times Upshot columnist Toni Monkovic talks to PredictWise prognosticator David Rothschild about the state this year that will decide the presidential election, and it's looking more and more like that state will not be Ohio or Florida, but Pennsylvania Rothschild argues. We get into the weeds here on electoral tipping points and probabilities, but the bottom line is if Clinton wins the state, she's nearly guaranteed the White House...but the same goes for Trump.
Q. Based on the PredictWise state polling probabilities, the entire election could boil down to Pennsylvania. If Hillary Clinton wins the state, she’ll probably be president. If Donald J. Trump wins there, he’ll probably be president — because such a victory would suggest he’d also win Ohio, Florida, North Carolina. Today, PredictWise gives Clinton a 78 percent chance to win the state. This is close to The Upshot forecast(85 percent). Can you give some more insight into what makes Pennsylvania so important and what signs you’ll be looking for in the state in the next few weeks?
A. Pennsylvania has been the most likely tipping-point state since midsummer.
It has been the state to put Hillary Clinton over 270 electoral votes, should she win all of the other more likely states for her. Conversely, it’s also the state that would put Trump over the hump, if he wins all of the states that are more likely for him.
Every day, I run 100,000 simulations of the election. I use the probability of each state going for Clinton or Trump, then I mix that with a correlation matrix that defines the relationships between the states. And every day since late July, Pennsylvania has been the state that most frequently is won by the candidate who wins the election. Currently, there are just 6 percent of scenarios where Clinton wins Pennsylvania but loses the election, and just 3 percent of scenarios where Clinton loses Pennsylvania and wins the election.
Since Pennsylvania is more secure for the Clinton camp than other swing states, it’s unlikely that Clinton loses Pennsylvania and wins either Florida or Ohio or other states to make up for the necessary electoral votes. And Trump could take Florida and Ohio and North Carolina, and go over the top with some other combination of swing states. But Pennsylvania is his most likely route.
What I will be looking for in Pennsylvania over the next few weeks is simple: polls in Pennsylvania; polls in Ohio, which have similar demographics (and a lot of polling); and national polls that correlate heavily among the key swing states.
Furthermore, I will be paying special attention to the crosstabs of national polls that focus on key swing demographics for Pennsylvania, when available and reliable, including white women. Beyond the polling for the presidential election, the ups and downs of the Pennsylvania Senate race could be important. The Democratic challenger, Katie McGinty, currently enjoys a slight lead, and that get-out-the-vote campaign will heavily overlap with Clinton’s.
Further, we will learn more soon about ad buys and get-out-the-vote operations in the state. Currently Clinton enjoys a comfortable margin in both categories. If they make a difference — and if they ever make a difference it will be this year with a massive disparity in both advertising and get-out-the-vote efforts — it should give Clinton a slight advantage over the polling average.
In other words, while I've talked a lot about Ohio this year, the state that will decide the election seems to be the Keystone State. Florida decided 2000, Ohio decided 2004, and most likely Pennsylvania will decide 2016.
The interview goes on to talk about swing voters (they don't exist at this late stage in the game other than the Johnson/Stein third party vote), the ground game (Clinton's advantage there may be worth as many as two percentage points nationally), and why Rothschild and his team failed so miserably on the Brexit vote...a sobering lesson that all the punditry in the world is essentially meaningless in the end. People either will vote or will not, and we'll see who they vote for in November.